1. Field of the Invention
The present invention relates to a chuck for holding and/or transferring or transporting a plate member such as a silicon wafer and to a suction board or disk used for such a chuck.
2. Description of the Related Art
Chucks for transferring a plate member between conveyors or between the inside and outside of a process system are known as described in Japanese Patent Publications No. 62-70141, No. 61-156749 and the like. A plate member is transported by bringing vacuum utilizing a suction device in direct contact with the plate member in order to suck and hold it and not to drop it during transportation. For example, a thin wafer disk is frequently transported during semiconductor manufacture processes. As a chuck using such a suction device is used, the suction device becomes in contact with a wafer to suck it. Therefore, a large amount of dirt or contamination is attached to the area of the wafer in contact with the suction device. The dirt attached to the suction device is also transferred and attached to the surface of another wafer as if the suction area of the former wafer is printed. The dirt hinders the succeeding manufacture processes and may cause a considerably lowered manufacture yield.